Combined frame and back light module

ABSTRACT

A combined frame for housing at least a lamp with one end connected to a power cord is provided. The combined frame comprises a lower frame and an upper frame. The lamp is positioned between the upper frame and the lower frame. The lower frame has an angled cable groove that encloses the power cord from the lamp. One end of the power cord is exposed outside the lower frame. The upper frame is positioned over the lower frame. Through the angled cable groove, the power cord is prevented from sliding in the axial direction of the lamp by any unintended external force and hence pulling power cable away from the lamp. This invention also provides a back light module comprising a light-guiding plate and the aforementioned lamp and combined frame.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of a prior application Ser. No.10/250,287, filed Jun. 20, 2003, now pedning, which claims the prioritybenefit of Taiwan application serial no. 92104142, filed on Feb. 27,2003.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a combined frame and a back lightmodule. More particularly, the present invention relates to a combinedframe capable of fastening the power cord of a lamp and preventing thesolder joints joining the power cord and the lamp from loosening up anda back light module deploying the combined frame.

2. Description of Related Art

Thanks to the many breakthroughs in semiconductor technologies and theintroduction advanced display devices, multi-media have been developedat an exceedingly fast pace. In the past, cathode ray tube (CRT) wasalmost the only commercially available display device due to its superbquality and low price. However, with the advent of personal computers,other factors related to a display device such as spatial occupation,power consumption and environmental safety become important consideringfactors. Because CRT is basically a bulky and power gusting device, ithas been gradually replaced by radiation free, high image quality, slimand power efficient displays such as liquid crystal displays (LCD).

FIG. 1 is a diagram showing the structural layout of a conventional backlight module. As shown in FIG. 1, the back light module 100 comprises alight-guiding plate (LGP) 110, a lamp 120, a reflector 130, an opticalfilm 140 and a combined plastic frame 200. The light-guiding plate 110furthermore comprises a light-incidenting surface 112, a light-diffusingsurface 114 and a light-emitting surface 116. The lamp 120 is set upnext to the light-incidenting surface 112 of the light-guiding plate110. Light from the lamp 120 enters the light incidenting surface 112 ofthe light-guiding plate 110 to be diffused and reflected by thelight-diffusing surface 114. Finally, the diffused and reflected lightleaves the light-guiding plate 110 through the light-emitting surface116. In other words, the light-guiding plate 110 is capable oftransforming linear light rays from the lamp 120 into a planar lightsource for illuminating the entire surface of a liquid crystal panel(not shown) uniformly.

The reflector 130 is positioned on one side enclosing the lamp 120 sothat light emitted from the lamp 120 is concentrated towards thelight-incidenting surface 112 of the light-guiding plate 110. Theoptical film 140 is positioned above the light-emitting surface 116 ofthe light-guiding plate 110 for increasing luminance of the back lightmodule 100.

The combined frame 200 comprises of an upper frame 210 and a lower frame220. The lower frame 220 supports the light-guiding plate 110, the lamp120 and the reflector 130. The sidewall 222 of the lower frame 220furthermore comprises a plurality of protrusions 224. The upper frame210 has a plurality of fasteners 212 that corresponds in position to theprotrusions 224. Each fastener 212 has an opening 214 suitable forfastening with a protrusion 224 so that the upper frame 210 and thelower frame 220 are tightly engaged together. In addition, the upperframe 210 has a window 216 for exposing the light emitted from thelight-emitting surface 116 of the light-guiding plate 110 so that aliquid crystal panel (not shown) above the upper frame 210 isilluminated by a planar light source. In brief, through the engagementof the upper frame 210 and the lower frame 220, the light-guiding plate110, the lamp 120 and the reflector 130 are bound together into anintegrative back light module 100.

FIGS. 2A and 2B are diagrams showing the outlet end of a lamp-linkedpower cord in a conventional back light module. As shown in FIGS. 2A and2B, one end of the lamp 120 resting on the lower frame 220 is oftensoldered to a power cord 122. The power cord 122 emerging from the backlight module 100 is usually connected to a bias voltage so that the lamp120 is powered. Furthermore, a stationing block 226 having a cablegroove 228 is attached to one side of the lower frame 220. The powercord 122 is buried inside the cable groove 228 so that the other end ofthe power cord 122 is exposed outside the lower frame 220. In addition,the upper frame 210 also has a cover plate 218 that covers thestationing block 226 when the upper frame 210 and the lower frame 220are fastened together through the fasteners 212 and the protrusions 224.

Since the cable groove 228 in a conventional stationing block 226 has astraight design, the following defects are produced:

1. With a straight cable groove design, the power cord inside the cablegroove is free to slide in the axial direction of the lamp and oftenleads to a shift in the power cord position.

2. With a straight cable groove design, the power cord inside the cablegroove is often subjected to unintended jerking forces while the moduleis being assembled or tested. Consequently, the soldering points mayloosen up or be exposed resulting in current leakage. If the power cordis pulled too hard, the solder joint may break apart leading to lampfailure.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide acombined frame and a back light module capable of stationing theposition of a power cord and preventing any external forces fromshifting the power cord, loosening up or exposing solder joints.

To achieve these and other advantages and in accordance with the purposeof the invention, as embodied and broadly described herein, theinvention provides a combined frame for supporting at least a lamp withone end connected to a power cord. The combined frame comprises a lowerframe and an upper frame. The lower frame has an angled groove forhousing the power cord from the lamp such that one end of the power cordis exposed outside the lower frame. The upper frame engages with thelower frame above the lower frame.

This invention also provides a back light module. The back light modulecomprises a light-guiding plate, at least a lamp and a combined frame.The light-guiding plate has at least a light-incidenting surface, atleast a light-diffusing surface and a light-emitting surface. One end ofthe lamp is connected to a power cord. The lamp is positioned on oneside of the light-incidenting surface. The lamp provides a beam of lightto the light-incidenting surface of the light-guiding plate. Afterpassing through the light-diffusing surface, the light travels on to thelight-emitting surface and emerges from the light-guiding plate. Thecombined frame comprises a lower frame and an upper frame. The lowerframe has an angled groove for housing the power cord from the lamp suchthat one end of the power cord is exposed outside the lower frame. Theupper frame engages with the lower frame above the lower frame. Theupper frame also has a window for exposing the light emerging from thelight-emitting surface of the light-guiding plate.

According to one embodiment of this invention, the lower frame has astationing block. The angled groove is located inside the stationingblock. The upper frame has a cover plate for covering the stationingblock. In addition, the angled groove has one or a multiple of corners.The corner can be a right-angled corner, an acute corner or an obtusecorner. Moreover, the angled groove has a plurality of position-limitingprojections for restraining the movement of the power cord.

According to one embodiment of this invention, the sidewall of the lowerframe has a plurality of protrusions and the upper frame has a pluralityof fasteners that correspond in position to the respective protrusions.Each fastener has an opening for engaging with a protrusion so that theupper frame and the lower frame can be fastened together through thefasteners and the protrusions. Furthermore, each protrusion has a slantsurface for guiding the fasteners over the block so that the opening onthe fastener can click onto the protrusion with ease.

According to one embodiment of this invention, an optical film is alsoformed on the light-emitting surface of the light-guiding plate forincreasing the luminance of the back light module. In addition, areflector is stalled on one side of the lamp. The reflector encloses thelamp so that light emitted from the lamp is concentrated towards thelight-incidenting surface of the light-guiding plate. Moreover, areflective plate is installed at the bottom of the light-guiding platefor increasing the reflectivity and diffusive strength of thelight-diffusing surface of the light-guiding plate. Therefore, overallutilization of light in the back light module is increased.

In this invention, a cable groove having one or a multiple of angledcorners are used to house the power cord of the lamp. The angled groovedesign restrains the movement of the power cord so that the power cordis prevented from sliding in the axial direction of the lamp within thegroove. Furthermore, any unintended external force pulling at the end ofthe power cable is transmitted to the corner regions only. Hence, thesolder joint connecting the power cord to the lamp is prevented frompulling loose or breaking away from the lamp.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a diagram showing the structural layout of a conventional backlight module.

FIGS. 2A and 2B are diagrams showing the outlet end of a lamp-linkedpower cord in a conventional back light module.

FIG. 3 is a diagram showing the structural layout of a back light moduleaccording to one preferred embodiment of this invention.

FIGS. 4A and 4B are diagrams showing the outlet end of a lamp-linkedpower cord according to one preferred embodiment of this invention.

FIGS. 5A to 5C are top views showing a few angled grooves designedaccording to the preferred embodiment of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts.

FIG. 3 is a diagram showing the structural layout of a back light moduleaccording to one preferred embodiment of this invention. As shown inFIG. 3, the back light module 300 comprises a light-guiding plate 310, alamp 320, a reflector 330, an optical film 340, a reflective plate 350and a combined frame 400. The light-guiding plate 310 has alight-incidenting surface 312, a light-diffusing surface 314 and alight-emitting surface 316. The light-diffusing surface 314 has aplurality of V-shaped notches or a plurality of recess points (notshown). The lamp 320 is, for example, a cold cathode fluorescent lamp(CCFL) installed on one side of the light-incidenting surface 312 of thelight-guiding plate 310. Light emitted from the lamp 320 enters thelight-incidenting surface 312 of the light-guiding plate 310 and thenget diffused or reflected by the light-diffusing surface 314 beforeemerging from the light-emitting surface 316. Therefore, thelight-guiding plate 310 coverts the light emitted from the lamp, whichis a linear light source, to a planar light source so that a liquidcrystal panel (not shown) is uniformly illuminated.

The reflector 330 is installed on one side enclosing the lamp 320. Thereflector 330 concentrates the light from the lamp 320 towards thelight-incidenting surface 213 of the light-guiding plate 210. Theoptical film 340 is positioned over the light-emitting surface 316 ofthe light-guiding plate 310 for increasing luminance level of the backlight module 300. The reflective plate 350 is installed at the bottom ofthe light-guiding plate 310 for increasing the reflectivity anddiffusive strength of the light-diffusing surface 314 and hence improvesoverall utilization of light in the back light module 300. In otherwords, the reflector 330, the optical film 340 and the reflective plate350 together provides a planar light source that improves the luminancelevel and hence the resolution of the liquid crystal display.

The combined frame 400 is a carrier for holding the light-guiding plate310, the lamp 320 and the reflector 330. The combined frame 400comprises of an upper frame 410 and a lower frame 420. The sidewall 422of the lower frame 420 has a plurality of protrusions 424 and the upperframe 410 has a plurality of corresponding fasteners 412. Each fastener412 has an opening 414 for fastening with a protrusion 424 so that theupper frame 410 and the lower frame 420 are tightly meshed together. Inaddition, each protrusion 424 has a slant surface 424 a for guiding thefastener 412 over the slant surface 424 a so that the opening in thefastener 412 and the protrusion 424 can easily fasten with each other.Furthermore, the upper frame 410 has a window 416 for exposing thelight-emitting surface 316 of the light-guiding plate 310 so that theplanar light source emerging from the light-emitting surface 316 canpass on to the liquid crystal display (not shown) over the upper frame410.

In short, the combined frame 400 formed by meshing the upper frame 410with the lower frame 420 also fixes the relative positions of thelight-guiding plate 310, the lamp 320 and the reflector 330 so that anintegrative back light module 300 is produced.

FIGS. 4A and 4B are diagrams showing the outlet end of a lamp-linkedpower cord according to one preferred embodiment of this invention. Asshown in FIGS. 4A and 4B, one end of the lamp 320 resting on the lowerframe 420 is often soldered to a power cord 322. The power cord 322emerging from the back light module 300 is usually connected to a biasvoltage so that the lamp 320 is powered. Furthermore, a stationing block426 having an angled cable groove 428 is attached to one side of thelower frame 420. The power cord 322 is buried inside the angled cablegroove 428 so that the other end of the power cord 322 is exposedoutside the lower frame 420. In addition, the upper frame 410 also has acover plate 418 that covers the stationing block 426 when the upperframe 410 and the lower frame 420 are fastened together through thefasteners 412 and the protrusions 424.

As shown in FIG. 4A, the angled cable groove 428 has two corners (thatis, the groove 428 bends twice). The corners are right-angled bends.When the power cord 322 is enclosed within the angled cable groove 428,the power cord 322 is prevented from moving in the axial direction ofthe lamp 320 by the corners. Moreover, the angled cable groove 428 mayhave additional position-limiting bumps 428 a pressing against the sideof the power cord 322 further limiting any movements. Due to the bendingcorner design of the cable groove 428, any unintended external forces atthe end of the power cord 322 will be applied to the corner regioninstead of acting directly on the solder joint between the power cord322 and the lamp 320. In other words, the solder joint between the powercord 322 and the lamp 320 is prevented from pulling loose, exposing orbreaking away.

FIGS. 5A to 5C are top views showing a few right-angled grooves designedaccording to the preferred embodiment of this invention. As shown inFIGS. 5A to 5C, the angled cable groove 428 inside the stationing block426 is not limited to the design in FIG. 4A with two right-angledcorners. For example, the angled cable groove 428 may be designed tohave a single corner (as shown in FIG. 5A), a total of three corners (asshown in FIG. 5B) or a total of four corners (as shown in FIG. 5C).Similarly, cable bumps (not shown) can be fitted inside the angled cablegroove 428 to restrain the power cord 322.

In this embodiment, the angled cable groove is shown to haveright-angled corners. However, other types of corners can be used aswell. For example, an acute corner or an obtuse corner or corners withother geometric shapes that can restrain the movement of a power cablecan be used.

In addition, the combined frame according to this invention is appliedto a back light module for positioning a lamp, a reflector and alight-guiding plate and fixing a power cable attached to the lamp.Obviously, the applications of the combined frame are not limited to aback light module. The combined frame can also be used to house amodular light source having one or a multiple of lamps therein andstationing the power cord within.

In summary, the combined frame and back light module of this inventionhas at least the following advantages:

1. In this invention, the power cord leading from the lamp is housedinside grooves within the lower having one or a multiple of corners. Theangled groove design restrains the movement of the power cord so thatthe power cord is prevented from sliding in the axial direction of thelamp inside the groove.

2. With an angled cable groove in the lower frame, any unintendedexternal force pulling at one end of the power cord is transmitted tothe corner regions only. Hence, the solder joint connecting the powercord to the lamp is protected.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

1. A combined frame for housing at least a lamp with one end connectedto a power cord, comprising: a lower frame having an angled cable groovehaving at least two corners, wherein the power cord is enclosed withinthe angled cable groove such that the end of the power cord is exposedoutside the lower frame; and an upper frame covering the top section ofthe lower frame so as to engage with the lower frame.
 2. The combinedframe according to claim 1, wherein the lower frame furthermorecomprises a stationing block such that the angled cable groove is formedinside the stationing block.
 3. The combined frame according to claim 2,wherein the upper frame furthermore comprises a cover plate such thatthe cover plate covers the top section of the stationing block.
 4. Thecombined frame according to claim 1, wherein each of the corners of theangled cable groove is selected from a group consisting of a rightcorner, an acute corner and an obtuse corner.
 5. The combined frameaccording to claim 1, wherein the interior of the angled cable groovefurthermore has a plurality of bumps for restraining any movement in thepower cord.
 6. The combined frame according to claim 1, wherein thesidewalls of the lower frame furthermore have a plurality of protrusionsand the upper frame furthermore has a plurality of correspondingfasteners each with an opening thereon so that each protrusion canfasten onto the opening of a corresponding fastener so that the upperframe and the lower frame are fastened together.
 7. The combined frameaccording to claim 6, wherein each protrusion furthermore has a slantsurface for guiding the fastener so that the opening in the fastener cansmoothly click onto the protrusion.
 8. A combined frame having at leasta lamp therein, comprising: a lower frame having an angled cable groove;an upper frame covering the top section of the lower frame so as toengage with the lower frame; at least a lamp disposed between the lowerframe and the upper frame; and a power cord connected with the lamp andenclosed within the angled cable groove such that one end of the powercord is exposed outside the lower frame.
 9. The combined frame having atleast a lamp therein according to claim 8, wherein the angled cablegroove has at least two corners.
 10. The combined frame having at leasta lamp therein according to claim 9, wherein each of the corners of theangled cable groove is selected from a group consisting of a rightcorner, an acute corner and an obtuse corner.
 11. The combined framehaving at least a lamp therein according to claim 8, wherein the lowerframe furthermore comprises a stationing block such that the angledcable groove is formed inside the stationing block.
 12. The combinedframe having at least a lamp therein according to claim 11, wherein theupper frame furthermore comprises a cover plate such that the coverplate covers the top section of the stationing block.
 13. The combinedframe having at least a lamp therein according to claim 8, wherein theinterior of the angled cable groove furthermore has a plurality of bumpsfor restraining any movement in the power cord.
 14. The combined framehaving at least a lamp therein according to claim 8, wherein thesidewalls of the lower frame furthermore have a plurality of protrusionsand the upper frame furthermore has a plurality of correspondingfasteners each with an opening thereon so that each protrusion canfasten onto the opening of a corresponding fastener so that the upperframe and the lower frame are fastened together.
 15. The combined framehaving at least a lamp therein according to claim 14, wherein eachprotrusion furthermore has a slant surface for guiding the fastener sothat the opening in the fastener can smoothly click onto the protrusion.